The attractiveness of 4D printing in the medical field: Revealing scientific and technological advances in design factors and applications

Currently, there is an increasing demand in the medical field for low-cost, high-quality products as well as personalized solutions, and different manufacturing methods are being investigated to provide innovative solutions. Four-dimensional (4D) printing is a promising technology that could overcome the challenges associated with the applications of three-dimensional printing in regenerative medicine and biomedical devices. A revolution is expected in this regard, and it is essential to keep abreast of the latest developments. Under this context, the purpose of this paper is to reveal scientific and technological advances of 4D printing in the medical field using a competitive technology intelligence (CTI) methodology. To this end, publications were analyzed from the Scopus database between January 1, 2017, and May 9, 2023. The main trends were identified for both design factors and applications. In the first case, the following were considered: 4D printing methods, external stimuli, materials, mathematical models, and interaction mechanisms. In contrast, in the second case, the applications of 4D printing involved were considered: drug delivery systems, stents, and scaffolds. The obtained design factors results included improvements in mechanical properties of hydrogels by adding magnetic nanoparticles, biopolyurethane, and other materials, the development of cell-friendly bioprinting methods to print cellular structures, and the use of theoretical-experimental approaches to predict shape deformation of structures. While for applications, results included advances in the development of expandable drug delivery systems, fabrication of stents for the treatment of vascular and tracheal stenosis, and the design of scaffolds to treat cartilage defects and bone regeneration. This study provides insights to researchers, academics, and companies involved in research and development as well as innovation that are looking for new solutions to improve health by incorporating breakthrough technologies such as 4D printing.